Water-bearing domestic appliance comprising a drainage pump and corresponding drainage pump

ABSTRACT

A water-bearing domestic appliance includes a retainer for retaining items to be subjected to a liquid treatment and a drainage pump having an inlet through which liquid enters the drainage pump. The drainage pump also includes an outlet through which liquid exits the drainage pump, a pump impeller for conveying liquid along a passage through the drainage pump extending from the inlet to the outlet, and a separate chamber located upstream of the pump impeller relative to the direction of flow of liquid through the passage. The separate chamber has an internal diameter and an external diameter and has respective radial bores on its external diameter and in the vicinity of its internal diameter.

The invention relates to a water-bearing domestic appliance comprising adrainage pump which has a pump impeller used to convey liquid and to adrainage pump with a pump impeller.

In water-bearing domestic appliances such as dishwashers or washingmachines a drainage pump is used to pump away dirty cleaning liquid. Atthe end of a drainage process air enters into the pump housing. Thissucked-in air is concentrated at the centre of the rotating pumpimpeller as a result of the pressure conditions and results in abreakaway or reduced conveying flow. Any remaining quantities of liquidare thus not pumped away by the drainage pump or are pumped away with adelay. Every drainage pump shows this problem which results in operatingdisturbances or requires other expensive or disadvantageous measures.

A ventilation device for a drainage pump in dishwashers is known fromthe German Utility Model 94 06 463 U1, which has a ventilation openingon the suction side for air enclosed at the centre of the drainage pumpto flow out. This ensures that functional disturbances on restarting thedrainage pump are avoided.

It is the object of the invention to provide a water-bearing domesticappliance of the type described wherein the conveyance of air and liquidand the pumping capacity of the drainage pump are improved and furtherto provide a corresponding drainage pump.

The object is solved according to the invention for the water-bearingdomestic appliance by the features of claim 1 and by the furtherindependent claim for the drainage pump. Further developments of theinvention are given in the dependent claims.

Starting from a water-bearing domestic appliance with a drainage pumpwhich has a pump impeller and a drainage pump with a pump impeller, thedraining pump according to the subject matter of the invention has aseparate chamber which is located behind the pump impeller in relationto the direction of flow of liquid and is equipped with respectiveradial bores on its external diameter and in the vicinity of itsinternal diameter. As a result of the separate chamber, a liquid flow isadvantageously formed from the external diameter to the internaldiameter and then into the centre of the pump impeller whereby the airis better vortexed with the liquid and the mixture thus formed is moreeffectively pumped away. The pumping capacity and the suction behaviourof the drainage pump are improved, especially without externalexpenditure and without delaying of the conveying medium caused byventilation openings or ventilation channels in the pump housing.

According to a favourable further development of the invention, theseparate chamber is arranged as close as possible to the pump impeller.The liquid flow in the flow circuit of the drainage pump from theexternal diameter to the internal diameter of the separate chamber andfrom there to the centre of the pump impeller for mixing liquid with aircan thus be further improved.

According to a further favourable embodiment of the invention, aplurality of bores are provided for the external diameter and theinternal diameter. The bores for the external diameter and internaldiameter are preferably provided so that they are each distributeduniformly on the separate chamber. Both measures positively influencethe liquid flow in relation to the flow circuit of the drainage pump.

A further embodiment of the invention whereby the bores have a smallcross-section has proved to be of particular value.

The previously described features are advantageously also used in thedrainage pump with an impeller according to the invention and especiallyin dishwashers and washing machines.

The invention provides a water-bearing domestic appliance with adrainage pump which has a pump impeller used to convey liquid, whereinthe conveyance of air and liquid and the pump capacity of the drainagepump are improved and further provides a corresponding drainage pumpwith a pump impeller.

The subject matter of the invention is explained in detail withreference to an exemplary embodiment shown in the figures. In detail thefigures show:

FIG. 1 shows a drainage pump 1 according to the invention of awater-bearing domestic appliance according to the invention;

FIG. 2 shows a section of the chamber pertaining to the drainage pumpwith an exemplary arrangement of bores; and

FIG. 3 shows the water-bearing domestic appliance according to theinvention and showing a retainer thereof for retaining items to besubjected to a liquid treatment.

FIG. 1 shows a drainage pump 1 of a water-bearing domestic applianceaccording to the invention, the water-bearing domestic appliancetypically being a dishwasher or a washing machine and beingrepresentatively shown in FIG. 3 as a dishwasher. The water-bearingappliance has a pump housing 2 with a pump impeller 3. An inletconnecting piece 4 via which liquid, for example water, can be conveyedinto the pump impeller 3 or air can be sucked in, runs in the directionof the axis of the pump impeller 3 and is moulded on the input side ofthe pump housing 2. A motor housing 5 with the drive motor for the pumpimpeller 3 for example with straight vanes which can be set in rotationis also located in the direction of the axis of the pump impeller 3 andis moulded on the other side of the pump housing 2. The drainage pump 1also has an outlet connecting piece 10 which is arranged radially inrelation to the axis of the pump impeller 3.

According to the subject matter of the invention, the water-bearingdomestic appliance has a drainage pump 1 with a separate chamber 6 whichis located behind the pump impeller 3 in relation to the direction ofthe conveyed liquid, i.e., the axis of the pump impeller 3, and isprovided with respective radial bores 7′ and 7″ on its external diameter11 and in the vicinity of its internal diameter 12. As a result of theseparate chamber 6, a liquid flow, identifiable from the arrows in FIG.1, is advantageously produced from the external diameter 11 to theinternal diameter 12 and then into the centre 9 of the pump impeller 3,whereby the air is better vortexed with the liquid and the mixture 8thus produced is pumped away more effectively. The pump capacity and thesuction behaviour of the drainage pump 1 are improved, especiallywithout external expenditure and without any delay of the conveyingmedium caused by ventilation openings or ventilation channels in thepump housing 2.

In a favourable fashion the separate chamber 6 is arranged as close aspossible to the pump impeller 3 whereby the liquid flow in the flowcircuit—see arrows—of the drainage pump 1 from the external diameter 11to the internal diameter 12 of the separate chamber 6 and from there tothe centre 9 of the pump impeller 3 for mixing liquid with air can thusbe further improved. A plurality of bores 7′, 7″ are provided for theexternal diameter 11 and the internal diameter 12 and preferablyprovided so that they are each distributed uniformly on the separatechamber 6. Both measures positively influence the liquid flow—seearrows—in relation to the flow circuit of the drainage pump 1.

For illustration FIG. 2 shows a section of the separate chamber 6pertaining to the drainage pump with an exemplary arrangement of bores.Thus, one bore 7′ is located on the external diameter 11 of the chamber6 whereas another bore 7″ is located near the internal diameter 12 ofthe chamber 6. In total, the chamber 6 has respectively four uniformlydistributed radial bores 7′ and 7″ both on its external diameter 11 andalso on its internal diameter 12. The arrows show the behaviour of theliquid flow from the external diameter 11 with bore 7′ where a higherpressure prevails to the internal diameter 12 with bore 7″ where a lowerpressure prevails and from there to the centre of the pump impeller. Ithas proved to be of particular value if the bores have a smallcross-section so that all the bores have a diameter of 3.5 mm each forexample.

The invention provides a water-bearing domestic appliance with adrainage pump 1 which has an impeller wheel 3 used to convey liquid,wherein the conveyance of air and liquid and the pump capacity of thedrainage pump 1 are improved and further provides a correspondingdrainage pump 1 with a pump impeller 3.

1. A water-bearing domestic appliance comprising: a retainer forretaining items to be subjected to a liquid treatment: and a drainagepump having an inlet through which liquid enters the drainage pump, anoutlet through which liquid exits the drainage pump, a pump impeller forconveying liquid along a passage through the drainage pump extendingfrom the inlet to the outlet, and a separate chamber located downstreamof the pump impeller relative to the direction of flow of liquid throughthe passage, the separate chamber having an internal diameter and anexternal diameter and having respective radial bores on its externaldiameter and in the vicinity of its internal diameter, and the operationof the drainage pump being such that liquid received into the drainagepump via the inlet flows into an area of the passage at which the pumpimpeller is operating and thereafter flows further along the passagewith at least some of the liquid flowing into contact with the separatechamber downstream of the pump impeller and entering and passing throughthe radial bores of the separate chamber.
 2. The water-bearing domesticappliance according to claim 1, wherein the separate chamber is locatedrelatively closely adjacent the pump impeller.
 3. The water-bearingdomestic appliance according to claim 1, wherein a respective pluralityof bores are provided on the external diameter of the separate chamberand another respective plurality of bores are provided on the internaldiameter of the separate chamber.
 4. The water-bearing domesticappliance according to claim 1, wherein the bores for the externaldiameter and the internal diameter are distributed uniformly on theseparate chamber.
 5. The water-bearing domestic appliance according toclaim 1, wherein each of the bores has a small cross-section.
 6. Thewater-bearing domestic appliance according to claim 1, wherein thewater-bearing domestic appliance is a dishwasher and the retainer forretaining items to be subjected to a liquid treatment is operable toretain items to subjected to a dishwasher liquid treatment.
 7. Thewater-bearing domestic appliance according to claim 1, wherein thewater-bearing domestic appliance is a washing machine and the retainerfor retaining items to be subjected to a liquid treatment is operable toretain items to subjected to a washing machine liquid treatment.
 8. Adrainage pump comprising: an inlet through which liquid enters thedrainage pump; an outlet through which liquid exits the drainage pump; apump impeller for conveying liquid along a passage through the drainagepump extending from the inlet to the outlet; and a separate chamberlocated downstream of the pump impeller relative to the direction offlow of liquid through the passage, the separate chamber having aninternal diameter and an external diameter and having respective radialbores on its external diameter and in the vicinity of its internaldiameter, and the operation of the drainage pump being such that liquidreceived into the drainage pump via the inlet flows into an area of thepassage at which the pump impeller is operating and thereafter flowsfurther along the passage with at least some of the liquid flowing intocontact with the separate chamber downstream of the pump impeller andentering and passing through the radial bores of the separate chamber.9. The drainage pump according to claim 8, wherein the separate chamberis located relatively closely adjacent the pump impeller.
 10. Thedrainage pump according to claim 8, wherein a respective plurality ofbores are provided on the external diameter of the separate chamber andanother respective plurality of bores are provided on the internaldiameter of the separate chamber.
 11. The drainage pump according toclaim 8, wherein the bores for the external diameter and the internaldiameter are distributed uniformly on the separate chamber.
 12. Thedrainage pump according to claim 8, wherein each of the bores has asmall cross-section.
 13. The drainage pump according to claim 8, whereinthe drainage pump is operable in a water-bearing domestic appliance inthe form of a dishwasher.
 14. The drainage pump according to claim 8,wherein the drainage pump is operable in a water-bearing domesticappliance in the form of a washing machine.